Monitoring Trends in Conception Rate

Abstract

Monitoring results of a breeding program, especially evaluating trends in conception rate, should be an integral part of a reproductive herd health program.¹ "Conception rate" is defined here as the number of pregnancies resulting from a given number of services which when multiplied by 100 becomes a percentage. The number of services used as the denominator should be all services in a given period including those used in cows that ultimately leave the herd without conceiving. Counting only those services used in cows that eventually conceive gives an artificially high result and one that is unduly affected by culling. This policy also complicates and delays conception rate calculation as no decision can be made about the inclusion or exclusion of unsuccessful services in cows still being bred.